London Wasps will put their European Cup ambitions on the line tonight against a fledgling Welsh team formed barely six months ago.

The Celtic Warriors tore up tournament form guides with a stunning 14-9 victory over Wasps atCauseway Stadium on Sunday.

And if they can repeat that feat on home soil in Bridgend, then Wasps' quarter-final ambitions will be left hanging by a thread.

Lawrence Dallaglio's men would have to win their final two Pool Six games - one of which is away against last season's beaten European Cup finalists Perpignan - and still hope that the Warriors and Perpignan drop points elsewhere.

"The return match is going to be a massive game," said Wasps scrumhalf and former Wales captain Rob Howley.

Wasps boss Warren Gatland has reacted to the weekend defeat by making several changes, with England World Cup centre Stuart Abbott starting his first game since Christmas, Mark van Gisbergen returning at full back and prop Will Green and flanker Jonny O'Connor handed starts up front.

The Warriors will make a decision this evening between scrumhalves Sililo Martens and Gareth Cooper - depending on weather conditions.

The Neath-Swansea Ospreys, bottom of Pool Two following three successive defeats, have injury concerns surrounding skipper Scott Gibbs and full back Gavin Henson for tonight's clash against European Cup holders Toulouse at The Gnoll.

Former Wales and Lions centre Gibbs has an ear drum problem, while Henson is battling to overcome a calf injury.

Also tonight, Northampton visit the Borders in Pool Four, with coach Wayne Smith having shuffled his back division.

New Zealander Bruce Reihana moves from centre to full back, Mark Tucker starts in midfield, and Smith goes with a half back combination of Paul Grayson and Mark Robinson.